Nokia just posted its quarterly results - including shipped devices - and it's not looking good. Massive losses, sales dropping, and no growth in Lumia sales in the US. The company is losing money hand-over-fist, and with Windows Phone 8 still months away, the company warns the next quarter will be just as bad.

S40 is what brought and brings most money. Symbian was hardly a cash cow, just a minor part of what Nokia sold, with quite bad return of investment (seriously, R&D costs for Symbian alone were larger, 2-3 years ago or so, than the entire Apple R&D budget; all for mediocre results) and constantly dwindling unit costs. It was hardly viable already back then.

And "Qt everywhere" sounds nice, but Nokia tried to push people to make Qt apps for Symbian for two years or so, also with a then-solid promise of being able of smoothly move to Maemo/Meego. Hardly any apps resulted, nobody cared.
Things similar to "Qt layer" on top of main OS greatly delay Android upgrades; and here it wouldn't even be in Android-native APIs.